OBJECTIVE: To understand the information in scent marks and how scent regulates social interactions. RESULTS We have shown that cotton-top tamarins can discriminate between the odors of familiar and unfamiliar females and further more they react differently to cycling versus reproductively suppressed unfamiliar females. We are completing a study to evaluate odors and social memory, to see if animals that used to live with each other but have been living apart for periods of 1-3 years respond to each others' odors as familiar or unfamiliar, and whether odors of unfamiliar kin are treated differently than those of familiar kin We have completed a study olfactory communication in wild common marmosets in Brazil. Data on the contexts and identities of markers as well as responses to marks have been obtained on more than 1900 marking events. Subordinate monkeys mark more at territory boundaries than dominants, and odors placed by dominant animals at feeding sites may affect reproductive inhibition in subordinate females. FUTURE DIRECTION To complete data analyses of both field and captive data, to develop HPLC methods to determine the types of chemicals used to provide different types of information.